Field
The present application relates to an optical assembly of an endoscope comprising an objective tube and at least one optical element held in the objective tube. Moreover, the present application relates to an endoscope comprising an optical assembly, a method for producing an optical assembly, and the use of a shape-memory material.
Prior Art
An investigated area in front of a distal end of the endoscope shaft is observed with an endoscope objective. The endoscope objective is typically sealed with a protective window against the exterior. The endoscope objective depicts the investigated area on an image sensor. Alternatively, the image is projected by relay lenses to the proximal region of the endoscope. The image sensor or eyepiece is located there for directly observing the investigated area. With flexible endoscopes, the optical imaging occurs on a flexible bundle of optical fibers.
The endoscope objective and the relay lenses will be generally termed optical assemblies of the endoscope in the following. They normally comprise several lenses or lens groups that are arranged sequentially in the longitudinal direction of the endoscope and/or are held in an objective or system tube.
DE 10 2008 038 619 B3 discloses an endoscope objective with three lens groups that are accommodated with circumferential play in an objective tube. The objective tube comprises an interior flange that serves as a stop for the lens groups in the longitudinal axial direction. In the radial direction, the lenses are fixed by adding a low-viscosity adhesive in the gap between the lens, or respectively lens group, and objective tube through holes in the objective tube. After the adhesive cures, there is a secure connection between the lens group and the objective tube.